A bollard is typically employed to prevent vehicular traffic inward or past the point of the bollard. Accordingly, any building or structure that requires protection may be protected by a plurality of bollards deployed about the periphery thereof. From a design standpoint, bollards must be strong enough to prevent and/or substantially slow movement of a vehicle between the bollard and the structure to be protected. Furthermore, periodically, vehicular access is desired and therefore the bollards must be designed in retractable fashion, thereby permitting vehicular travel over the recessed bollard.
Several retractable bollard designs are known and employ various deployment methods including hydraulic or pressurized gas means. Hydraulic bollards are disadvantaged by seals that sometimes deteriorate and result in a loss of hydraulic fluid pressure. On the other hand, bollards supported by gaseous pressure are disadvantaged by the loss of volume sometimes exhibited as ambient temperatures decrease. As with a loss of hydraulic pressure, the efficacy of the bollard comes into question as the supporting fluidic pressure is reduced. Furthermore, retractable bollards that function based on fluidic pressure must be maintained to ensure operability over extended periods of time.